246 COMPOSITAE. 



Akenes linear, more or less 



4-angled. 

 Involucral bracts 



united. 417. ERIOPHYLLUM, 278. 



Involucral bracts sep- 

 arate. 418. RIGIOPAPPUS, 279. 

 Akenes obpyramidal. 



Receptacle bristly. 419. GAILLARDIA, 279. 

 Receptacle naked. 420. HELENIUM, 279. 



363. TRAGOPOGON. 



Stout leafy-stemmed and usually branching biennials or per- 

 ennials, with milky juice; leaves entire, grass-like, clasping; 

 flowers yellow or purple, in large solitary heads; involucre simple, 

 of several equal bracts; pappus of numerous long-plumose 

 bristles; corollas all ligulate; akenes narrowly fusiform, 5-10- 

 ribbed. long-beaked. 



Tragopogon porrifolius L. Salsify. Oyster Plant. Biennial, glabrous 

 throughout, the stout stems about 1 m. high; leaves lanceolate, attenuate from 

 the broader somewhat clasping base, 10-15 cm. long; peduncles long and stout, 

 swollen under the head; involucral bracts lanceolate, acuminate, 4-5 cm. long, 

 exceeding the violet rays; outer akenes roughened, the inner smooth, 1 cm. 

 long, attenuate into a beak of equal length; pappus brownish, as long as the 

 beak, plumose nearly to the tip. Escaped from gardens and spreading. 



364. PTILORIA. 



Leafy-stemmed and branching herbs, with milky juice and 

 small heads; flowers pink or white; receptacle without chaff or 

 bristles; pappus of plumose or partly plumose bristles or rarely 

 chaffy awns or narrow scales; corollas all ligulate; akenes short, 

 truncate at both ends, about 5-ribbed or angled. 



Pappus bristles fuscous, short-plumose; annual. P. paniculata. 



Pappus bristles white, long-plumose; perennial. P. tenuifolia. 



Ptiloria paniculata (Nutt.) Greene. Annual, erect, divaricately branched, 

 40-80 cm. high; leaves linear, sessile, entire or the lower ones pinnatifid, 2-6 

 cm. long, or much reduced on the flowering branches; heads 3-8-flowered, 

 numerous, in loose panicles, short-pedicelled; involucre 8-9 mm. long, the 

 outer scales very short; receptacle naked; akenes roughened, 4-5 mm. long; 

 pappus grayish-brown, of 15-25 bristles, plumose nearly to the broadened 

 base, a little longer than the akene. Bluffs of Snake River. 



Ptiloria tenuifolia (Torr.) Raf. Stems herbaceous, slender, ascending, 

 much branched, 20-40 cm. high, from a stout woody root; leaves narrowly 

 linear, mostly entire; heads mostly terminating the slender branches; involucre 

 8-10 mm. high; pappus bright white, very plumose; akenes much as in P. pani- 

 culata. In dry ground, infrequent. 



365. PTILOCALAIS. 



Puberulent or glabrous perennials, leafy at the base with 

 usually laciniate leaves and long-peduncled heads, nodding in the 



